The Schroeder German patent drawing is the best explanation, but there is a trade secret involved. I only know how I did it in my tonearm. A pole piece is attached to the end of each magnet. The pole piece is a piece of steel which is the same diameter as the magnet. The magnets are inside differently shaped aluminum parts.
I know very little about shielding and containing of magnetic fields. Maybe somebody else can enlighten us on the subject?
Last practical advice for DIY dudes other than mechanics:
Easy way to drill holes perpendicular to a wall of a cylinder:
Place the aluminum part of the wand on partially (1/4”) open milling vise (A mechanic would use a V-block). Clamp the piece down. Run small (3/16”) end-mill across the top of the cylinder wall to create tiny flat surface where the hole is supposed to be drilled. Mark exact center of that flat spot and drill 3/32” vertical hole through the cylinder. Next, without moving the vise, drill 3/8” hole just deep enough to accomodate the pole piece and magnet.
I will be gone for a while.
Marek
I know very little about shielding and containing of magnetic fields. Maybe somebody else can enlighten us on the subject?
Last practical advice for DIY dudes other than mechanics:
Easy way to drill holes perpendicular to a wall of a cylinder:
Place the aluminum part of the wand on partially (1/4”) open milling vise (A mechanic would use a V-block). Clamp the piece down. Run small (3/16”) end-mill across the top of the cylinder wall to create tiny flat surface where the hole is supposed to be drilled. Mark exact center of that flat spot and drill 3/32” vertical hole through the cylinder. Next, without moving the vise, drill 3/8” hole just deep enough to accomodate the pole piece and magnet.
I will be gone for a while.
Marek
In reference to SY's comment, building a working model from a patent without permission is always an infringement. This came directly from one of our patent lawyers. This was in response to the oft quoted mis-conception that there is a provision in the US patent code for building a model for "educational" purposes. This provision is mythical.
Experimental exception to patents
To my knowledge, the AD lawyer is right, it's not law, but it's precedent going back to the 19th century, with dozens of citeable court decisions. It has been limited in recent years by the Roche decision, but that seems pretty far from the sort of things we're looking at. There was a case with Duke University headed to the Supreme Court where the boundaries of experimental exception were being really pushed, but I don't know how that ended up.
But yeah, ask a lawyer.
To my knowledge, the AD lawyer is right, it's not law, but it's precedent going back to the 19th century, with dozens of citeable court decisions. It has been limited in recent years by the Roche decision, but that seems pretty far from the sort of things we're looking at. There was a case with Duke University headed to the Supreme Court where the boundaries of experimental exception were being really pushed, but I don't know how that ended up.
But yeah, ask a lawyer.
Greg Nuspel said:
If the claims of the original patent can be read on your device (or chemical, process, etc.), then you are infringing. In other words, read the claims and look at your invention. If part of your invention is described by the claims and is within the limitations of the claims, it infringes. You can cerrtainly patent improvements, but that gives you no right to use them if they require a prior patent to work. It does give you the the right to prevent others, including the original patent holders, from using the improvements.
Sheldon
Right, the law is one thing but court decisions change things that's why you need lawyers and their libraries. Reminds me of the Bridgeman vs. Corel decision where museums were told that their fancy prints or photos of ancient paintings can't be copyrighted no mater how much trouble it is to make them. Not necessiarily obvious from the law. In fact I just got a 2007 calender of 19th century Japanese prints where only Bridgeman has removed the copyright notice.
Hi again,
I did a little research on magnetic shielding. I am not going to rebuild my tonearms as they are plying nicely without shielding and without high permeability pole pieces. But I think it would be a good idea to place the magnets in little cups made from nickel-iron-molybdenum alloy. What do you think? Let’s say a cup with walls 0,5mm and bottom 2mm thick.
I am working on a new super composite platter for my turntable, I will post it if it works.
Marek
I did a little research on magnetic shielding. I am not going to rebuild my tonearms as they are plying nicely without shielding and without high permeability pole pieces. But I think it would be a good idea to place the magnets in little cups made from nickel-iron-molybdenum alloy. What do you think? Let’s say a cup with walls 0,5mm and bottom 2mm thick.
I am working on a new super composite platter for my turntable, I will post it if it works.
Marek
concerning patents:
At least in Europe it is allowed to USE any idea covered by an unexpired patent. You may build the thing described in the patent and use it for your own purposes. But you are not allowed to use it in a commercial way, as soon as you wand to earn mony with the thing described, you have to have the permission of the owner of the patent. Or you have to wait for the moment the patent expires.
I think - but I am not sure, that the laws are like that all over the world.
Best regards
floric
At least in Europe it is allowed to USE any idea covered by an unexpired patent. You may build the thing described in the patent and use it for your own purposes. But you are not allowed to use it in a commercial way, as soon as you wand to earn mony with the thing described, you have to have the permission of the owner of the patent. Or you have to wait for the moment the patent expires.
I think - but I am not sure, that the laws are like that all over the world.
Best regards
floric
Floric said:
This probably the consensus throughout Europe, but I'm not at all surprised that US multimillion corporate lawyers have been able to force court decisisons that gives precedence to the opposite.
As far as I know, throughout Europe, you can build a copy of any patented device, but you can NOT go commercial. This may also apply in the case you want to trade your "thingie", even for parts cost, but I'm not sure about this case. Also, the patent in question has to be issued for the country in question, i.e. there has to be either a world wide patent, or a patent issued for the specific country in question. Thus a general US patent really don't apply to Europe, unless the issued patent specifically says so ( and the corresponding patent fee is paid!!!)
AuroraB said:
No court decisions are necessary (BTW this issue probably has never gone to court), the law grants an "exclusive licence" and does not have clauses for DIY'ers. Certainly using patented art for barter as you say is probably not legal under any laws. It is true that you guys in Europe don't need to worry about people in the US that have not paid the considerable EU fees ($40,000+).
As an aside copyright law offers no protection for "inventions" only patents do. Those disclimers that dozens of people use like "permission is granted for personal use only" have no legal standing at all.
scott wurcer said:
My understanding was that the patent had to disclose sufficient detail about the invention to enable a person knowledgeable in the field to apply it. It strikes me that claiming that actually doing so is always an infringement prevents testing of whether the patent really does disclose sufficient detail. But perhaps that is precisely the intention...
EC8010 said:
No, I think you are correct, but I'd be interested to hear an actual legal opinion. Simple logic dictates that one would be able to duplicate (as opposed to practice) the invention in order to study it and perhaps come up with improvements. After all, that's the trade off for exclusivity, you teach others your methods. I think the distinction may lay in what use the model is put to. And study may require that variations on the invention would be required for testing.
I think it is correct that one cannot legally build a model of the invention to simply use it for practical purposes, or to avoid purchasing a commercial version - even if there is no intent to sell it or to use it in a commercial operation.
In practice, no one goes after a single individual for building a model strictly for their own use. Would rarely, if ever, be worth the cost.
Sheldon
Sheldon said:
Typical strategy would be to buy a working model and improve all you want. Also on the up side, reverse engineeering is protected by law. It is common to sell complete breakdowns of IC's for instance, process, circuit, and all with impunity. So in my world once you have a "real" schematic simulation tools can be used to analyze and improve or work around.
As too your last statement, I think that is what any sensible person would conclude. These discussions are mostly academic.
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